1moon

the moon : the large round object that circles the Earth and that shines at night by reflecting light from the sun

: a large round object like the moon that circles around a planet other than the Earth

Full Definition of MOON

1

aoften capitalized: the earth's natural satellite that shines by the sun's reflected light, revolves about the earth from west to east in about 291⁄2 days with reference to the sun or about 271⁄3 days with reference to the stars, and has a diameter of 2160 miles (3475 kilometers), a mean distance from the earth of about 238,900 miles (384,400 kilometers), and a mass about one eightieth that of the earth —usually used with the